Archive
Article
Geologica Carpathica, 2024, vol. 75, no. 2
Distribution of rare earth elements among rock-forming and accessory minerals: A case study of Variscan granites from the Krušné Hory Mts., Czech Republic
Abstract
Eight granite samples representing the main petrographic and geochemical types of Variscan granites from the Krušné Hory/Erzgebirge area were studied to decipher the distribution of rare-earth-elements (REE) among all rock-forming, minor, and accessory minerals. The chemical composition (REE contents) of minerals was determined using electron microprobe and laser ablation ICP MS, while the quantitative abundance of individual minerals was determined by automated mineralogy (TIMA technology). Monazite and xenotime + zircon are dominant hosts of both LREE and HREE respectively, especially in strongly peraluminous S-type granites. In less-fractionated Ca-richer facies, allanite is also an important carrier of LREE. In slightly peraluminous A-type granites, monazite + fluorite (including its alteration products) dominates as LREE hosts, while fluorite (including its alteration products), with small contributions of zircon and xenotime, hosts the HREE. The importance of rock-forming silicates for REE distribution is limited; the relatively highest contribution was found in plagioclase (up to approx. 15 % of LREE in S-type granites).
Keywords:
granites, rare-earth elements, rock-forming minerals, accessory minerals
Pages:
83 - 97
Published online:
26. 6. 2024